Re: [PATCH v7 10/24] drm/rockchip: dw_hdmi: Add support for hclk

From: Sascha Hauer <s.hauer@pengutronix.de>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	Benjamin Gaignard <benjamin.gaignard@collabora.com>,
	Peter Geis <pgwipeout@gmail.com>,
	Sandy Huang <hjc@rock-chips.com>,
	linux-rockchip@lists.infradead.org,
	Michael Riesch <michael.riesch@wolfvision.net>,
	kernel@pengutronix.de, Andy Yan <andy.yan@rock-chips.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v7 10/24] drm/rockchip: dw_hdmi: Add support for hclk
Date: Fri, 25 Feb 2022 11:49:24 +0100	[thread overview]
Message-ID: <20220225104924.GC19585@pengutronix.de> (raw)
In-Reply-To: <47ddcaf3-4544-2b7c-a2f6-1f6346907f33@gmail.com>

On Fri, Feb 25, 2022 at 01:26:14PM +0300, Dmitry Osipenko wrote:
> 25.02.2022 10:51, Sascha Hauer пишет:
> > The rk3568 HDMI has an additional clock that needs to be enabled for the
> > HDMI controller to work. The purpose of that clock is not clear. It is
> > named "hclk" in the downstream driver, so use the same name.
> > 
> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> > ---
> > 
> > Notes:
> >     Changes since v5:
> >     - Use devm_clk_get_optional rather than devm_clk_get
> > 
> >  drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c | 16 ++++++++++++++++
> >  1 file changed, 16 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
> > index fe4f9556239ac..c6c00e8779ab5 100644
> > --- a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
> > +++ b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
> > @@ -76,6 +76,7 @@ struct rockchip_hdmi {
> >  	const struct rockchip_hdmi_chip_data *chip_data;
> >  	struct clk *ref_clk;
> >  	struct clk *grf_clk;
> > +	struct clk *hclk_clk;
> >  	struct dw_hdmi *hdmi;
> >  	struct regulator *avdd_0v9;
> >  	struct regulator *avdd_1v8;
> > @@ -229,6 +230,14 @@ static int rockchip_hdmi_parse_dt(struct rockchip_hdmi *hdmi)
> >  		return PTR_ERR(hdmi->grf_clk);
> >  	}
> >  
> > +	hdmi->hclk_clk = devm_clk_get_optional(hdmi->dev, "hclk");
> > +	if (PTR_ERR(hdmi->hclk_clk) == -EPROBE_DEFER) {
> 
> Have you tried to investigate the hclk? I'm still thinking that's not
> only HDMI that needs this clock and then the hardware description
> doesn't look correct.

I am still not sure what you mean. Yes, it's not only the HDMI that
needs this clock. The VOP2 needs it as well and the driver handles that.

Sascha

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